begin 的過去式和過去分詞是什么

　　Work has begun on the construction of the new airport.

　　新機場的修建已經開工。

　　The firm has begun a major push into the European market.

　　這家公司已展開了對歐洲市場的重要攻勢。

　　It was tough talk, coming from a man who had begun the year in a hospital bed.

　　這話出自年初住進醫院的一位男子之口，語氣很強硬。

　　He began by making a few general observations about the report.

　　開頭他先對這個報告作了幾點概括性的評論。

　　Slowly, an image began to appear on the screen.

　　屏幕上慢慢地出現了一幅圖像。